The present invention relates to a device for manufacturing information recording mediums and more particularly to a device for manufacturing planar information recording mediums each having a transfer layer made of radiation curable layer-forming liquid resin coated over a flexible carrier member, to which a signal pattern is transcribed from a planar stamper carrying a corresponding information recording signal pattern.
It is well-known to use compression molding methods or injection molding methods for manufacturing information recording mediums, such as for example, audio-recording discs and video-recording discs. In these methods, a thermoplastic resin material, such as for example, polyvinyl chloride, is heated above its melting point and then cooled for setting an information recording medium. However, these methods offer disadvantages in that polyvinyl chloride, if it is used, is liable to be decomposed and generate a chlorine gas which corrodes a stamper having a signal pattern to be transcribed, when the material is heated above its melting point. In order to eliminate these disadvantages, a heavy investment is necessary for production facilities. Further, these methods also offer problems of noise, vibration and air pollution.
It is also well-known as the other methods of manufacturing information recording mediums to transcribe a signal pattern from a stamper to a layer made of thermoradiation or radiation curable resin. The method using the thermoradiation curable resin is time-consuming to set the resin itself and requires a heat source of large capacity. On the contrary, the method using the radiation curable resin is suitable to manufacture information recording mediums, since a relatively simple manufacturing device and a time saving procedure in comparison with the other conventional methods can be utilized. Japanese Patent Laid-Open Publication No. 33244/78 discloses a method of manufacturing information recording mediums by using radiation curable layer-forming liquid resin, wherein the liquid resin is uniformly applied over a stamper, then bound to a carrier member which is pressed by a holding plate, and finally set through irradiation of radiant rays. Further, Japanese Patent Laid-Open Publication No. 116105/78 discloses a method of manufacturing information recording mediums, wherein the liquid resin is dropped onto a stamper and then pressingly applied with a carrier member which is deformed into a shape having a convex sherical surface. Further, this Laid-Open Publication also discloses another method in which the layer made of the liquid resin is formed by pressing the carrier member onto the stamper through a roller. However, the methods proposed in the both publications are not complete and satisfactory procedures for manufacturing information recording mediums having high frequency recording signals, such as for example, video-recording discs, since air bubbles are liable to be mixed into the liquid resin applied over the carrier member, when the liquid resin is dropped onto the stamper and when the carrier member is pressed to the liquid resin on the stamper. Such air bubles mixed in the liquid resin pose a serious defect in the manufacturing of information recording mediums carrying high frequency recording signals, such as for example video-discs, since dropouts of the audio-sound or in the video-image to be reproduce are caused thereby. Further, the above-mentioned method is still relatively time-consuming, even though it is effective in the manufacturing of information recording mediums than other methods, and moreover cannot be expected to attain a sufficiently high productivity.